<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>svg</title>
</head>

<body>
  <p>内发光</p>

  <svg width="600" height="600">
    <defs>
      <!-- <filter id="inset-shadow" x="-50%" y="-50%" width="200%" height="200%">
        <feComponentTransfer in=SourceAlpha>
          <feFuncA type="table" tableValues="1 0" />
        </feComponentTransfer>
        <feGaussianBlur stdDeviation="4" />
        <feOffset dx="0" dy="1" result="offsetblur" />
        <feFlood flood-color="#0d619d" result="color" />
        <feComposite in2="offsetblur" operator="in" />
        <feComposite in2="SourceAlpha" operator="in" />
        <feMerge>
          <feMergeNode in="SourceGraphic" />
          <feMergeNode />
        </feMerge>
      </filter> -->

      <filter id="inset-shadow2">
        <feFlood flood-color="rgb(54,243,255)" />
        <feComposite in2="SourceGraphic" operator="out" />
        <feGaussianBlur stdDeviation="10" result="blur" />
        <feComposite operator="atop" in2="SourceGraphic" />
      </filter>
    </defs>
    <!-- <rect x=100 y=100 width=20% height=50% fill=transparent filter="url(#inset-shadow)" /> -->
    <text x="100" y="250" font-size="80" font-weight="bold" stroke="#0e0c24" filter="url(#inset-shadow2)">
      INSET SHADOW
    </text>
    <g transform="translate(100 100)">
      <path stroke="#36f3ff" stroke-shadow="red" fill="rgba(77,236,235,0.8)" filter="url(#inset-shadow2)"
        d="M-38.89087296526011,38.890872965260115A55,55,0,1,1,38.89087296526016,38.890872965260066L24.748737341529193,24.748737341529132A35,35,0,1,0,-24.74873734152916,24.748737341529164Z">
      </path>
    </g>
  </svg>

  <svg width="800px" height="600px">
    <defs>
      <filter id="inner-glow">
        <feFlood flood-color="red" />
        <feComposite in2="SourceAlpha" operator="out" />
        <feGaussianBlur stdDeviation="2" result="blur" />
        <feComposite operator="atop" in2="SourceGraphic" />
      </filter>
    </defs>

    <text filter="url(#inner-glow)" x="30" y="100" font-size="80" font-family="Sans-Serif" font-weight="bold"
      fill="rgb(77,236,235)">
      SVG Filters
    </text>

  </svg>
</body>

</html>